The present invention relates to a beverage dispensing apparatus of the type in which any one of several different beverages can be dispensed from a single beverage dispensing head by pressing a corresponding button. In particular, the present invention is related to flow control and shut-off devices used in a flow control manifold of such a beverage dispensing apparatus.
Hand-held beverage dispensers that provide the ability to dispense any of a number of different beverages by merely pressing a corresponding button are known. Such hand-held dispensers are sometimes referred to as bar guns. One such bar gun system is described in the assignee's issued U.S. Pat. No. 4,986,449, entitled: “Beverage Dispensing Apparatus,” the entire disclosure of which is hereby incorporated herein by reference.
Such bar guns typically include an upstream manifold having flow control elements and may also include flow regulators to regulate the flow rate of the beverage(s) through the beverage dispenser. The beverage dispenser can be hand-held or it can be in the form of a tower. A known beverage dispensing manifold is shown in FIG. 1. Illustrated in FIG. 1, is a one-piece shut-off screw (PM10-8) made of a polypropylene material disposed proximally to the inlets of the manifold. A typical manifold has a plurality of such shut-off screws, one for each flow channel. Typically, the shut-off screws may be rotated 90 degrees so as to stop product flow to the bar gun for, for example, servicing of the bar gun.
Also shown in FIG. 1, is a similar-looking flow control valve (lower part of FR-31), commonly referred to as a Brix valve or a Brix screw. In order for these valves and screws to control the flow and seal the screw chamber to prevent leakage, an o-ring is used in combination with the valve and the screw (e.g., see PM10-6). FIG. 2 illustrates a more detailed view of the known shut-off screw (PM10-8) and its associated o-ring (PM10-6). FIG. 2 also shows the o-ring when assembled with the shut-off screw. As is shown in FIG. 2, the shut-off screw has a necked-down portion to accommodate the o-ring. This reduced diameter portion can significantly weaken the part and render it more prone to twisting apart under abuse or when the shut-off screw is installed in the manifold with a high interference fit. The Brix valve, although lacking a through hole like the shut-off valve, also suffers from similar problems due to also having a necked-down portion used to accommodate an o-ring. Furthermore, the known flow control/shut-off device is made of polypropylene. As such, the part can get slightly deformed or compressed during its assembly with the manifold body, as the part is commonly made a bit oversized. During its use, the part can shrink or otherwise become deformed to such an extent that is does not provide a reliable leak-proof seal under standard operating pressures.